The present invention relates to a process for adding pharmaceutically active compounds to substrates. The present invention is particularly useful for substrates used in the manufacture of disposable absorbent articles, specifically suited for substrates used in the manufacture of tampons.
There are several methods of delivering pharmaceutically active compounds to their intended targets, including but not limited to oral, topical, and transdermal. Disposable absorbent articles can be used as vehicles for topical delivery to the vaginal canal, perineum, and related areas, as well as for treatment sites for the discharged fluids to come in contact with the pharmaceutically active compounds, as they are captured by the product.
Duchane, U.S. Pat. No. 3,796,219, discloses a water-soluble, thermoplastic composition for hygienic and medical applications, such as for use as an insertion aid coating for tampons and as the matrix structure for suppositories. The coating is stable in temperatures up to 65.degree. C., and it provides lubricity at temperatures below 65.degree. C. when exposed to shear forces, such as those present during insertion of the tampon. Duchane discloses the use of two olefinic diols, polyethylene glycol and propylene glycol in combination with hydroxypropyl cellulose (HPC) having a molecular weight of approximately 75,000. The resulting composition is stable at temperatures up to 65.degree. C. Von Bittera et al., U.S. Pat. No. 4,582,717, discloses a process for producing vaginal tampons containing a pharmaceutically active compound. The process involves preparing a material containing the active compound and additional formulation auxiliaries, heating the material to a temperature in excess of 40.degree. C., cooling the melt to 40.degree. C., and then injecting the cooled material into pre-warmed tampons. One of the formulation auxiliaries disclosed in von Bittera is polyethylene glycol (PEG) having moderate molecular weight. A common theme of the art shown above is the attempt to provide a coating that is stable above room temperature, but is liquid at or near body temperature (37.degree. C.). Brown-Skrobot, U.S. Pat. No. 5,679,369, discloses additives to tampons to inhibit the production of toxic shock syndrome toxin-1. The additives generally are not liquid at or near room temperature, and therefore, they require a carrier material, such as isopropyl alcohol. This technology represents an important advance in the art, but the disclosed process of applying the additive may require a recovery process to capture the volatile alcohol.
All of the art above requires either the use of significant energy or a volatile carrier material, to apply their respective coatings; thus a need still exists for a process for adding pharmaceutically active compounds to substrates or articles of manufacture, without the limiting requirements as stated.